Scratches in Horses: How To Treat Pastern and Heel Dermatitis

By Dr Duncan Houston

Pastern and heel dermatitis, often called scratches, mud fever, greasy heel, cracked heels, or dew poisoning, is one of the most frustrating lower-leg skin problems in horses.

It usually affects the skin around the heel, back of the pastern, fetlock, and sometimes the lower cannon bone. At first, it may look like a few harmless scabs. But once the skin becomes wet, cracked, infected, swollen, or painful, the condition can become slow to heal and difficult to control.

The most important thing to understand is that scratches is not one single disease. It is a skin reaction pattern. Mud, moisture, bacteria, fungi, mites, allergies, sunlight sensitivity, irritants, and heavy feathering can all contribute. UC Davis describes pastern dermatitis as a disease complex rather than one simple diagnosis, which is why the same treatment does not work for every horse. (Centre for Equine Health)

Quick Answer

Scratches in horses is inflammation of the skin around the pastern and heel, often causing scabs, redness, swelling, oozing, pain, itching, or lameness. Mild cases may improve with clipping, gentle cleaning, thorough drying, and vet-directed topical treatment. If the leg is swollen, hot, painful, oozing, lame, or not improving, a vet should examine the horse because deeper infection, mites, fungal disease, photosensitivity, or chronic lower-leg disease may be involved.

What Is Pastern and Heel Dermatitis?

Pastern and heel dermatitis is inflammation of the skin on the lower limb, most commonly at the back of the pastern and heel region.

You may hear it called:

• Scratches

• Mud fever

• Greasy heel

• Mud rash

• Cracked heels

• Dew poisoning

• Pastern folliculitis

These names are useful, but they can also be misleading. “Mud fever” makes it sound like mud is always the cause. In reality, mud and moisture are common triggers, but they are not the whole story.

Dermatitis simply means skin inflammation. Merck Veterinary Manual notes that dermatitis can be caused by irritants, allergens, trauma, and infections, including bacterial, viral, parasitic, or fungal causes. It also notes that resolving dermatitis requires identifying the underlying cause and treating secondary infections or complications. (Merck Veterinary Manual)

That is the clinical point: you are not just treating scabs. You are trying to work out why the skin barrier failed.

What Causes Scratches in Horses?

Scratches usually develops when the pastern skin becomes weakened, irritated, or damaged. Once the skin barrier is compromised, bacteria, fungi, mites, moisture, and irritants can move in.

Common causes and contributors include:

Purdue Veterinary Medicine notes that scratches is commonly linked to excessively moist or dirty environments, damp pastures, wet stalls, and repeated wetting and drying of the skin. It also highlights that draft horses with feathers or long fetlock hair are at higher risk because the hair retains moisture. (Purdue Vet School)

What Does Scratches Look Like?

The signs vary depending on the cause, severity, and how long the condition has been present.

Early signs may include:

• Small scabs at the heel or back of the pastern

• Red or tender skin

• Mild scaling

• Matted hair

• A greasy or crusty feel

• Sensitivity during grooming

More advanced signs include:

• Thick scabs

• Oozing or discharge under the crusts

• Swelling around the pastern or lower limb

• Heat in the leg

• Pain when touched

• Itching, stamping, rubbing, or chewing

• Hair loss

• Cracks or fissures in the skin

• Lameness

• Spread up toward the fetlock or cannon bone

UC Davis notes that pastern dermatitis may begin with redness, oozing, crusting, erosions, and ulcerations, followed by swelling. The skin may be itchy and sensitive, and lameness can occur in some cases. (Centre for Equine Health)

In practice, the decision point is simple: a few dry scabs are one thing. A hot, swollen, painful lower leg is a very different problem.

Severity Guide: How Worried Should You Be?

The real concern is not just the scabs. It is whether the skin inflammation has become painful, infected, deep, or associated with lameness.

What Else Can Look Like Scratches?

Not every scabby pastern is simple mud fever.

Important rule-outs include:

Chorioptic mites
Mites are especially common in heavily feathered horses. They can cause stamping, chewing, rubbing, crusting, hair loss, and thickened skin around the lower limbs. MSD Veterinary Manual describes chorioptic mange as the most common form of mange in horses, often affecting the distal limbs around the foot and fetlock. (MSD Veterinary Manual)

Ringworm or fungal infection
Fungal disease can cause crusting, scaling, hair loss, and spread between horses or through contaminated equipment.

Bacterial pastern dermatitis
This is common when the skin is wet, cracked, oozing, swollen, or painful.

Photosensitivity
White legs can become inflamed after sunlight exposure, sometimes because of plant toxins, liver disease, or immune-mediated skin disease.

Pastern leukocytoclastic vasculitis
This is an immune-mediated, often photo-aggravated condition that can affect the distal limbs and may need very different treatment.

Chronic progressive lymphedema
This is especially relevant in draft breeds, Friesians, and Gypsy Vanners. It can cause chronic lower-leg swelling, thickened skin, folds, nodules, recurrent infections, and ongoing pastern irritation. UC Davis notes that chronic progressive lymphedema causes progressive lower-leg swelling with skin folds, nodules, and ulcerations in some breeds. (Horse Report)

Hidden wounds or heel bulb injuries
A cut, puncture, or wire injury may be mistaken for dermatitis once scabs form.

The mistake I see most often is treating every pastern scab as the same condition. If the wrong cause is treated, the horse may improve briefly and then relapse.

When Is This an Emergency?

Scratches is not always an emergency, but some cases need urgent veterinary care.

Call your vet promptly if your horse has:

• Lameness

• Severe swelling

• Heat in the leg

• Pain when the area is touched

• Rapidly spreading lesions

• Deep cracks or ulceration

• Yellow or white discharge

• A foul smell

• Bleeding skin

• Fever

• Loss of appetite

• Depression or dullness

• Severe itching or self-trauma

• A suspected wound or puncture

• No improvement despite treatment

• More than one limb badly affected

Purdue advises veterinary attention when scratches is not responding to treatment, or when there is severe lameness, deep wounds, swelling, excessive heat, or white or yellow discharge. (Purdue Vet School)

If the horse is lame, swollen, hot, or systemically unwell, stop treating it like a cosmetic skin issue. That horse needs proper veterinary assessment.

How Vets Diagnose Pastern and Heel Dermatitis

Diagnosis starts with the pattern.

Your vet may ask:

• Which legs are affected?

• Did it start after wet weather or muddy turnout?

• Is the horse itchy, painful, or lame?

• Is the skin white or pigmented?

• Does the horse have heavy feathers?

• Is this seasonal?

• Has it happened before?

• Are other horses affected?

• What products have already been applied?

• Is there swelling, discharge, or heat?

Depending on the case, your vet may recommend:

• Skin scrapings for mites

• Tape tests

• Hair plucks

• Cytology to check for bacteria or yeast

• Bacterial culture

• Fungal culture

• Biopsy in chronic or unusual cases

• Radiographs if lameness or deeper disease is suspected

UC Davis notes that diagnosis may involve biopsy, bacterial and fungal cultures, skin scrapings for ectoparasites such as Chorioptes mites, and radiographs when other causes of lameness need to be ruled out. (Centre for Equine Health)

This is why recurring or severe scratches should not be managed by guesswork.

What Should You Do Right Now?

1. Inspect the Skin Properly

Part the hair and look at the actual skin.

Check for:

• Redness

• Scabs

• Crusts

• Moisture

• Oozing

• Swelling

• Heat

• Pain

• Cracks

• Hair loss

• Discharge

• Lameness

Take photos. They help you and your vet see whether the condition is improving or simply changing appearance.

2. Move the Horse to a Dry Environment

Dryness is one of the most important parts of recovery.

If possible:

• Keep the horse out of deep mud

• Use clean, dry bedding

• Avoid wet stalls

• Reduce turnout in wet grass during active flare-ups

• Dry the pasterns thoroughly after washing or turnout

UC Davis prevention guidance focuses on avoiding repeated moisture exposure, drying the pasterns well after bathing, keeping lower-leg hair clipped where appropriate, and avoiding long-term boots or wraps that trap moisture. (Centre for Equine Health)

3. Clip Long Hair if Needed

Clipping is not always popular, especially with feathered breeds, but it can be very useful.

Clipping helps:

• Reveal the true extent of the lesions

• Reduce trapped moisture

• Allow medication to reach the skin

• Make mites easier to detect

• Improve drying

• Make monitoring easier

Purdue recommends carefully clipping hair away from infected areas while avoiding scraping or breaking the skin. (Purdue Vet School)

4. Clean Gently, Not Aggressively

If the case is mild and the skin is not severely painful, gentle cleaning may help.

A vet may recommend an antibacterial shampoo such as chlorhexidine, povidone-iodine, or benzoyl peroxide, or an antifungal shampoo such as miconazole, depending on the suspected cause. Purdue advises letting medicated shampoo sit for about 10 minutes before gentle rinsing, avoiding rough scrubbing and harsh chemicals. (Purdue Vet School)

Do not scrub the skin raw. You are trying to calm the barrier, not punish it for being infected.

5. Dry the Area Thoroughly

This step is often underestimated.

After washing, pat the area dry with a clean towel. Do not leave wet hair, wet scabs, or damp feathers against the skin.

If the horse is repeatedly washed but never fully dried, the treatment can become part of the problem.

6. Do Not Pull Off Dry Scabs

Scabs can be painful and may cover raw tissue underneath.

If they need to be removed, soften them first and remove them gently. Some horses need sedation, pain relief, or veterinary help for safe cleaning.

Purdue’s rule of thumb is a good one: do not scratch scratches. Scabs can be massaged off carefully after softening, but they should not be pulled or picked. (Purdue Vet School)

7. Apply Medication Only as Directed

Topical treatment depends on the cause.

Your vet may recommend:

• Antibacterial ointment

• Antifungal treatment

• Anti-inflammatory medication

• Topical steroid combinations in selected cases

• Barrier cream

• Mite treatment

• Systemic antibiotics for deeper or severe infection

Do not layer multiple creams, sprays, oils, powders, and leftover medications together. That can irritate the skin, trap moisture, hide the true appearance of the lesions, and make diagnosis harder.

Should You Wrap Scratches?

Sometimes, but not automatically.

A wrap may help in selected cases by keeping medication in place and protecting the skin. But wraps and boots can also trap heat, moisture, and debris, which may worsen pastern dermatitis if used incorrectly.

Do not wrap unless your vet has advised it, especially if the skin is wet, oozing, swollen, or infected.

Purdue specifically advises not using wraps or boots that retain moisture around infected areas, and UC Davis also warns against long-term use of boots and wraps that trap moisture. (Purdue Vet School)

How Treatment Usually Works

A good treatment plan usually includes several parts.

Skin Access

Long hair or feathers may be clipped so the affected skin can be seen, cleaned, dried, and treated.

Gentle Cleansing

Medicated shampoo may be used if bacteria or fungi are suspected. The exact product and frequency should match the case.

Drying

The area must be dried properly after cleaning. This is not optional.

Targeted Topical Medication

This may include antibacterial, antifungal, anti-inflammatory, mite treatment, or barrier products depending on the diagnosis.

Systemic Medication

Oral antibiotics, anti-inflammatories, or other medications may be needed if the infection is deep, spreading, painful, or associated with lameness.

Environmental Change

If the horse remains in wet bedding, deep mud, or damp turnout, treatment may fail even if the medication is correct.

Common Mistakes Owners Make

Treating Every Case as Mud Fever

Mud is common, but it is not the only cause. Mites, fungi, photosensitivity, allergies, bacterial infection, and chronic lower-leg disease can all look similar.

Picking Scabs Too Aggressively

This causes pain, bleeding, and more inflammation. Scabs should be softened first and removed only when appropriate.

Over-Washing

Washing can help, but constant washing keeps the area wet. Drying is just as important as cleaning.

Wrapping Wet Skin

A wrap over damp, infected skin can trap moisture and worsen the condition.

Using Harsh Products

Bleach, caustic scab removers, strong disinfectants, essential oils, and random stable-yard mixtures can damage inflamed skin.

Ignoring Mites in Feathered Horses

If a feathered horse is stamping, chewing, rubbing, or repeatedly relapsing, mites should be considered.

Waiting Too Long

Early scratches is usually easier to treat. A swollen, lame, infected leg is a bigger problem.

How To Prevent Scratches

Prevention is about protecting the skin barrier and reducing moisture.

Useful steps include:

• Check pasterns regularly during grooming

• Keep legs as dry as practical

• Avoid prolonged turnout in deep mud

• Improve drainage around gates and water troughs

• Use clean, dry bedding

• Dry legs before stabling

• Avoid repeated wetting and drying

• Clip heavy feathers in recurrent cases if advised by your vet

• Do not leave boots or wraps on damp legs

• Do not share boots, towels, or grooming tools between affected horses

• Use fly control if insects trigger irritation

• Use sun protection strategies for white legs when needed

• Investigate recurring cases rather than repeating the same failed treatment

Purdue recommends dry footing, dry bedding, drying legs before stabling, avoiding moisture-retaining boots or wraps, clipping long leg hair in some horses, and frequent leg checks for early infection. (Purdue Vet School)

The boring management details matter. Dry footing and clean bedding may not sound exciting, but they beat chasing chronic scratches around the yard for months.

Will My Horse Recover?

Many horses recover well when the cause is identified early and treatment is consistent.

The best outcomes usually happen when:

• The case is treated early

• The underlying cause is identified

• The skin is kept dry

• Secondary infection is controlled

• Mites and fungal disease are not missed

• The horse is not left standing in mud

• Harsh products are avoided

• Follow-up happens if the leg is not improving

UC Davis notes that early, accurate diagnosis and appropriate treatment give the best chance of success and help prevent severe chronic changes. Secondary bacterial infections are common and can complicate diagnosis, treatment, and recovery. (Centre for Equine Health)

Chronic cases can take longer. If the horse has heavy feathering, chronic progressive lymphedema, repeated wet exposure, or long-standing thickened skin, the goal may be long-term control rather than a one-time cure.

FAQs

Can scratches in horses go away on its own?

Very mild cases may improve if the trigger is removed and the area is kept clean and dry. If the skin is swollen, painful, oozing, itchy, spreading, or causing lameness, it should not be left to resolve on its own.

Should I remove the scabs?

Do not pull off dry scabs. They should be softened first and removed gently only when appropriate. If your horse is painful, sedation or veterinary help may be needed.

What is the best treatment for scratches?

There is no single best treatment for every horse. The right treatment depends on whether the cause is moisture, bacteria, fungus, mites, allergy, sunlight sensitivity, irritants, or chronic lower-leg disease.

Should I wrap pastern dermatitis?

Only if your vet advises it. Wraps can help in selected cases, but they can also trap moisture and worsen the problem if used incorrectly.

When should I call a vet?

Call a vet if there is lameness, swelling, heat, pain, discharge, severe itching, spreading lesions, deep cracks, fever, or no improvement despite initial care.

Final Thoughts

Scratches in horses is common, but it should not be treated casually.

A few dry scabs may be manageable with early care, a dry environment, gentle cleaning, and proper monitoring. But once the skin becomes swollen, painful, infected, itchy, oozing, or associated with lameness, the condition needs veterinary attention.

The real key is not just removing scabs. It is identifying the cause, protecting the skin barrier, keeping the area dry, treating infection or mites when present, and preventing the same conditions from recreating the problem.

Healthy pasterns are built on boring fundamentals: dry legs, clean bedding, early checks, and targeted treatment rather than random products.

If you are unsure whether your horse’s scratches are mild, infected, mite-related, or urgent, ASK A VET™ can help you work through the signs and decide what to do next.